Various strain measuring devices are known. They can generally comprise a strainable member to which a load is imparted and to which a strain gage is fixed. Among then are devices which comprise an annular gage ring having strainable beam members and flexing beam members. The flexible beam members interconnect ring portions.
Also among the known devices are dual beam sensing members which include spaced end wall members connected integrally by parallel spaced beam members, which beam members are relatively flexible or bendable in one direction only. One of the end walls is generally attached to a support structure and the other end wall is operatively or directly attached to a shaft.
Representative of the art is U.S. Pat. No. 6,216,547 (2001) to Lehtovaara which discloses a load sensor comprising an annular gauge ring comprising an annular inner ring portion and an annular outer ring portion and having strainable beam members and flexing beam members. The flexible beam members interconnect ring portions.
Reference is also made to applicant's copending U.S. patent application Ser. No. 10/262,035 filed Sep. 30, 2002 which discloses a hubload transducer having an strainable ring disposed in a coplanar manner between an inner ring and an outer ring.
Also know are pulleys for measuring torque loads comprising a cylindrical shape connected to a pulley with the other end connected to a shaft and having strain gages attached to the cylindrical shape.
Representative of the art is Japanese patent application publication number 2001099271 which discloses a cylindrical shape connected to a pulley with the other end connected to a shaft and having strain gages attached to the cylindrical shape.
The prior art does not teach hubload and torque transducers combined to operate on a system basis. Further, the hubload transducers are relatively complex comprising flexing beam members and strainable beam members. The prior art torque transducer lacks means to torsionally isolate the cylindrical portion from the other supporting structures.
What is needed is a method and apparatus for measuring an operating belt span tension using a hubload transducer and a torque transducer. What is needed is a method and apparatus for measuring a belt drive efficiency using a hubload transducer and a torque transducer. The present invention meets these needs.